RX8111 64k prototype cartridge was not published by Atari in 1988. B&C Computervisions published an uncommon pirate cartridge version in 1997. 3 variations of the pirate copy exist, one in a brown case the other in grey cases.
This game uses a bug in one of Atari's graphics chips to show 16 colors color in a monochrome mode 8 (320x192x2). Because of this, different models of Atari 8-bit computers display the game in a different set of colors.